As of MySQL 5.6.3, the Performance Schema instruments stages,
which are steps during the statement-execution process, such as
parsing a statement, opening a table, or performing a
filesort operation. Stages correspond to the
thread states displayed by
PROCESSLIST or that are visible in the
table. Stages begin and end when state values change.
Within the event hierarchy, wait events nest within stage events, which nest within statement events.
These tables store stage events: